1. Field of the Invention
The present invention relates to the CTI technology of setting a schedule for line connection through telephone networks.
2. Description of the Related Art
With the growing popularity of the Internet and LANs (Local Area Networks), a media signal of an exchange unit such as a voice/FAX message, etc. conventionally controlled only by an exchange unit, can be communicated between a computer terminal unit and a destination terminal unit (telephone terminal unit, FAX terminal unit, etc.) in a switching network (local area switching network and public switching network) by connecting the computer terminal unit to the exchange unit through a modem and a terminal adapter connected to the computer terminal unit, or through a server unit to which the computer terminal unit is connected in a network.
Recently, a technology has been developed to communicate in real time a voice message, etc. between computer terminal units connected to the Internet, a LAN, etc., without switching networks. This technology is recognized as a new technology replacing the conventional international telephone switching network.
Furthermore, an interface between a computer and an exchange unit is being standardized, and technology called CTI (Computer Telephony Integration) for controlling the storage/reproduction of a voice/FAX message when connecting a line or through a connected line by controlling a private branch exchange, etc. using a computer terminal unit such as a personal computer, a work station, etc. is being developed.
A camp-on service can be considered a part of the conventional CTI technology.
The camp-on service enables a retrial for a communications connection based on a specified scheduling (setting a time to come back to the office, specific time, etc.) when a destination terminal unit does not answer or when the terminal units such as telephone terminal units connected to a predetermined exchange unit are busy.
Implementing the camp-on service remarkably increases the operability of telephone communications etc. in and between organizations.
However, in the conventional camp-on service, terminal units allowed to receive a service are limited to those connected to the same exchange unit, or to those belonging to a switching network connected via a private line controlled by a No. 7 common line signal system, etc., and no services can be provided to terminal units connected via a public switching network such as a public telephone network, a public ISDN network, etc.
The technology of communicating between a computer terminal unit and a telephone terminal unit, etc. through a switching network, by connecting from the computer terminal unit to an exchange unit, enables the computer terminal unit to replace the conventional telephone terminal unit and FAX terminal unit, but does not realize an advanced CTI technology, for example, a camp-on service, including control of a destination terminal unit.
Furthermore, the technology of communicating a voice message, etc. in real time between computer terminal units connected to a network without an exchange unit realizes communications of a voice message, etc. through a connectionless network, which is quite different from a line switching network connected by an exchange unit, and belongs to a category different from the CTI technology for realizing a high-performance line switching network through an exchange unit.
Additionally, the CTI technology of controlling an exchange unit such as a private branch exchange, etc. using a computer terminal unit such as a personal computer, a work station, etc., has recently been standardized and high-level services from this technology are being prepared.